package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.pojo.SeckillVoucher;
import com.hmdp.pojo.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 王艺锡
 * @since 2024-05-05
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    private IVoucherOrderService proxy;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;


    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherorderHandler());
    }

    private class VoucherorderHandler implements Runnable{
        String queueName = "stream.orders";
        @Override
        public void run() {
            while(true){
                try {
                    //1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS stream.orders >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),//指定组名和消费者名称
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),//设置一次读取一条消息，阻塞时间为2s
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())//指定队列名字和读取方式(接着上次读取)
                    );
                    //2.判断消息是否获取成功
                    if(list == null || list.isEmpty()){
                        //如果获取失败，说明此时没有消息，继续下一次循环
                        continue;
                    }
                    //3.获取成功，可以下单
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    handlerVoucherOrder(voucherOrder);
                    //4.ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());

                } catch (Exception e) {
                   log.error("处理订单异常",e);
                   handlePendingList();
                }

            }
        }

        private void handlePendingList() {
            while(true){
                try {
                    //1.获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 STREAMS stream.orders 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),//指定组名和消费者名称
                            StreamReadOptions.empty().count(1),//设置一次读取一条消息
                            StreamOffset.create(queueName, ReadOffset.from("0"))//指定队列名字和读取方式(从pending-list中读未处理的消息)
                    );
                    //2.判断消息是否获取成功
                    if(list == null || list.isEmpty()){
                        //如果获取失败，说明此时pending-list中没有消息，跳出循环
                        break;
                    }
                    //3.获取成功，可以下单
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    handlerVoucherOrder(voucherOrder);
                    //4.ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());

                } catch (Exception e) {
                    log.error("处理订单异常",e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        ex.printStackTrace();
                    }
                }

            }

        }
    }


    private void handlerVoucherOrder(VoucherOrder voucherOrder){
        //1.获取用户
        Long userId = voucherOrder.getUserId();
        //2.创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //3.获取锁
        boolean isLock = lock.tryLock();
        //4.判断是否获取成功
        if(!isLock){
            log.error("不能重复下单!");
            return;
        }

        try {
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            lock.unlock();
        }
    }


    @Override
    public Result seckillvoucher(Long voucherId) {
        //获取用户id
        Long userId = UserHolder.getUser().getId();
        //获取订单id
        long orderId = redisIdWorker.nextId("order");
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(),String.valueOf(orderId)
        );
        //2.判断是否为0
        //2.1.不为0，没有购买资格
        int r = result.intValue();
        if (r != 0) {
            return Result.fail(r == 1 ? "库存不足!" : "不可重复下单!");
        }
        //2.2.为0，有购买资格，将下单信息保存到redis的消息队列
        //2.3.获取代理对象
       proxy = (IVoucherOrderService) AopContext.currentProxy();

        //3.返回订单id
        return Result.ok(orderId);
    }


   /* @Override
    public Result seckillvoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        //1.查询优惠券信息
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if(voucher.getBeginTime().isAfter(LocalDateTime.now())){
            return Result.fail("秒杀尚未开始!");

        }
        //3.判断秒杀是否结束
        if(voucher.getEndTime().isBefore(LocalDateTime.now())){
            return Result.fail("秒杀已经结束!");
        }
        //4.判断库存是否充足
        if(voucher.getStock() < 1){
            return Result.fail("库存不足!");
        }

        //锁用户id，在多并发的情况下也可以保证一个用户只能抢购一个券

        //获取锁对象
        //SimpleRedisLock simpleRedisLock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        //如果没有获取到锁
        if(!isLock){
            return Result.fail("不允许重复抢购!");
        }

        try {
            //创建代理对象，使用代理对象来调用这个方法，才可以保证事务的生效
            //Transactional事务注解能够生效是因为spring对当前类进行了动态代理
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            lock.unlock();
        }


    }*/

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        //5.一人一单
        //5.1.查询订单
        int count = query()
                .eq("user_id", userId)
                .eq("voucher_id", voucherOrder.getVoucherId())
                .count();
        //5.2.判断是否存在
        if (count > 0) {
            log.error("不能重复下单!");
            return ;
        }

        //5.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherOrder.getVoucherId())
                .gt("stock", 0)//增加乐观锁
                .update();
        if(!success){
            log.error("库存不足!");
            return;
        }

        //7.保存订单信息到数据库
        save(voucherOrder);
    }


}
